Method for optical design of a pair of ophthalmic lenses and pair of ophthalmic lenses thus obtained

Abstract

Disclosed is a method for optical design of a pair of ophthalmic lenses for correcting spherical and cylindrical refractive errors of the eyes of a wearer, including a step of defining the need for spherical and cylindrical correction of the wearer for various viewing distances, and a step of determining the spherical and cylindrical power of the ophthalmic lenses at viewing points with various proximities, in accordance with the correction needs of the wearer. The power of at least one of the two ophthalmic lenses is determined such as to limit the deviation obtained therebetween upon adding equivalent spherical power between the viewing points with various proximities and/or varying the cylindrical power vector between the viewing points with various proximities. Also disclosed is a pair of ophthalmic lenses designed according to such a method.

The invention claimed is: 
     
       1. A method for obtaining a pair of ophthalmic lenses for correcting cylindrical and spherical refractive defects of the two eyes of a wearer, including:
 a step of defining the cylindrical and spherical correction requirements of the wearer for various vision proximities, 
 a step of determining cylindrical and spherical powers of said ophthalmic lenses at vision points of various proximities, depending on the previously defined cylindrical and spherical correction requirements of the wearer, and
 a step of producing said ophthalmic lenses on the basis of the determined cylindrical and spherical powers, 
 
 wherein the powers of at least one of the two ophthalmic lenses are determined so as to limit the discrepancy obtained, between the two ophthalmic lenses of the pair, in at least one of the following quantities: 
 the equivalent spherical power addition between the vision points of various proximities, and 
 the variation in the cylindrical power vector between the vision points of various proximities. 
 
     
     
       2. The method as claimed in  claim 1 , wherein the discrepancy obtained in one and/or the other of said quantities is smaller than a predefined threshold value. 
     
     
       3. The method as claimed in  claim 2 , wherein the discrepancy between the two ophthalmic lenses of the pair in the equivalent spherical power addition between the vision points of various proximities is smaller than 0.25 diopters. 
     
     
       4. The method as claimed in  claim 2 , wherein the discrepancy between the two ophthalmic lenses of the pair in the equivalent spherical power addition between the vision points of various proximities is smaller than 0.125 diopters. 
     
     
       5. The method as claimed in  claim 1 , wherein the discrepancy in the variation in the cylindrical power vector between the vision points of various proximities is obtained by modifying the amplitude and/or the angle of the cylindrical power vector of one of the two ophthalmic lenses of the pair at a near-vision point. 
     
     
       6. The method as claimed in  claim 1 , wherein, the powers of at least one of the two lenses is also determined so as to limit the difference obtained, for the two ophthalmic lenses of the pair, between the equivalent spherical power addition and the addition requirement. 
     
     
       7. The method as claimed in  claim 6 , wherein the difference obtained between the equivalent spherical power addition and the addition requirement is smaller than 0.25 diopters. 
     
     
       8. The method as claimed in  claim 1 , wherein the determination of the cylindrical and spherical powers of said at least one of the two ophthalmic lenses at vision points of various proximities is carried out in increments of 0.125 diopters. 
     
     
       9. The method as claimed in  claim 1 , wherein the determining step is carried out so that the cylindrical and spherical powers, at the vision points of the various proximities, of the ophthalmic lens intended to be placed in front of the dominant eye of the wearer correspond to the cylindrical and spherical correction requirements at said vision points of the wearer. 
     
     
       10. The method as claimed in  claim 1 , wherein said vision points of various proximities correspond to far-vision, intermediate-vision and/or near-vision points of the wearer. 
     
     
       11. The method as claimed in  claim 1 , wherein said vision points of various proximities correspond to far-vision and near-vision points of the wearer, and the cylindrical and spherical correction requirements of the wearer are defined on the basis of a measurement of the cylindrical and spherical refraction in far vision and in near vision of the two eyes of the wearer. 
     
     
       12. The method as claimed in  claim 1 , wherein said vision points of various proximities correspond to far-vision and near-vision points of the wearer, and the cylindrical and spherical correction requirements of the wearer are defined on the basis of a measurement of the cylindrical and spherical refraction in far vision of the two eyes of the wearer and of a measurement of the cylindrical and spherical refraction in near vision of at least one eye of the wearer. 
     
     
       13. The method as claimed in  claim 12 , wherein said measurement of the cylindrical and spherical refraction in near vision is performed on the dominant eye of the wearer. 
     
     
       14. The method as claimed in  claim 1 , wherein the step of defining the requirements comprises a substep of defining cylindrical correction requirements of the wearer for various vision proximities, which substep is carried out after a step of limiting the discrepancy obtained, between the two ophthalmic lenses of the pair, in the equivalent spherical power addition. 
     
     
       15. A pair of ophthalmic lenses for correcting cylindrical and spherical refractive defects of the two eyes of a wearer, said pair of lenses being obtained according to an optical designing method as claimed in  claim 1 . 
     
     
       16. The method as claimed in  claim 2 , wherein the discrepancy in the variation of the cylindrical power vector is determined according to the following rules:
 one of the two ophthalmic lenses of the pair having a minimal variation in the cylindrical power vector, this minimal variation being lower than 0.15 diopters, the variation in the cylindrical power vector of the other ophthalmic lens of the pair is lower than 0.3 diopters, or 
 one of the two ophthalmic lenses of the pair having a minimal variation in the cylindrical power vector, this minimal variation being higher than or equal to 0.15 diopters, the variation in the cylindrical power vector of the other ophthalmic lens of the pair is lower than twice this minimal variation in the cylindrical power vector. 
 
     
     
       17. The method as claimed in  claim 2 , wherein the discrepancy in the variation in the cylindrical power vector between the vision points of various proximities is obtained by modifying the amplitude and/or the angle of the cylindrical power vector of one of the two ophthalmic lenses of the pair at a near-vision point. 
     
     
       18. The method as claimed in  claim 3 , wherein the discrepancy in the variation in the cylindrical power vector between the vision points of various proximities is obtained by modifying the amplitude and/or the angle of the cylindrical power vector of one of the two ophthalmic lenses of the pair at a near-vision point. 
     
     
       19. The method as claimed in  claim 4 , wherein the discrepancy in the variation in the cylindrical power vector between the vision points of various proximities is obtained by modifying the amplitude and/or the angle of the cylindrical power vector of one of the two ophthalmic lenses of the pair at a near-vision point. 
     
     
       20. A method for obtaining a pair of ophthalmic lenses for correcting cylindrical and spherical refractive defects of the two eyes of a wearer, including:
 a step of defining the cylindrical and spherical correction requirements of the wearer for various vision proximities, 
 a step of determining cylindrical and spherical powers of said ophthalmic lenses at vision points of various proximities, depending on the previously defined cylindrical and spherical correction requirements of the wearer, and 
 a step of producing said ophthalmic lenses on the basis of the determined cylindrical and spherical powers, 
 wherein the powers of at least one of the two ophthalmic lenses are determined so as to limit the discrepancy obtained, between the two ophthalmic lenses of the pair, in at least one of the following quantities:
 the equivalent spherical power addition between the vision points of various proximities, and 
 the variation in the cylindrical power vector between the vision points of various proximities, and 
 
 wherein the discrepancy in the variation of the cylindrical power vector is determined according to the following rules:
 one of the two ophthalmic lenses of the pair having a minimal variation in the cylindrical power vector, this minimal variation being lower than 0.15 diopters, the variation in the cylindrical power vector of the other ophthalmic lens of the pair is lower than 0.3 diopters, or 
 one of the two ophthalmic lenses of the pair having a minimal variation in the cylindrical power vector, this minimal variation being higher than or equal to 0.15 diopters, the variation in the cylindrical power vector of the other ophthalmic lens of the pair is lower than twice this minimal variation in the cylindrical power vector.